Viscosimeter



.Oct 13, 1936. H T, BOOTH 2,056,952

VISCOS IMETER` Filed Feb. '7, 1935 g Ala/7, 9? @wd 35 IBYt n 4 w 37 *i* ATTORNEYS Patented Oct. 13, 1936 UNITED STATES -PJrlazN'r oFFlcE VISCOSIMETER,

Harry T. Booth, Detroit, Mich., assignor to Lubrication Control Corporation, Chicago, Ill., a corporation of Delaware This invention relates to a viscoslmeter and has for an object a simple and efficient device for directly measuring the viscosity of fluid flowing through the device.

In a device embodying the invention, fluid is caused to pass successively through two ports, one comprising a friction tube, the resistance of which to liuid flow varies with the viscosity of the fluid and the other port comprising an orifice, the

resistance of which to fluid flow is substantially independent of the viscosity of the fiuid, these ports being arranged in either of two orders of succession.

Means are provided for supplying fluid to the first port at constant pressure and the pressure of the fiuid' between the two ports is applied to a pressure actuated viscosity indicator. The pressure of the fluid between the two ports is a function of the viscosity of the uid and the indio cator gives direct viscosity readings of the fluid flowing through the device.

Other objects, novel features and advantages of this invention will be apparent from the following speciflcation and accompanying drawing,

Z5 wherein:

Fig. 1 is a side elevation of an automobile engine having its lubricating system provided with a viscosimeter embodying the invention; and

Figs. 2 and 3 are enlarged vertical central sectional views of viscosimeters embodying the invention.

The internal combustion engine I0 is provided with an oil pan II from the lower portion of which a pipe I3 leads to the intake port of a pump I4. A pipe I5 leads from the outlet port of the pump I4. to the engine bearings (not shown). A relief valve may be connected to the pipe I5 for preventing the oil pressure in said pipe from exceeding a predetermined maximum.

L0 A pipe I6 leads from the pipe I5 to a casing I1 arranged in the upper part of the oil pan II. The left end of the casing I1 is closed by a plug I8. A skirted piston 30 is slidably mounted in the casing and the skirt is provided with ra- 5 dial ports 3I which communicate with a peripheral groove 32 in the outer face of the skirt. The position of the piston 30 with respect to the pipe I6 controls the flow of oil through said pipe into the interior of the piston. A plug 33 is held in ;0 the casing I1 by screws 34 and carries a friction' tube 35 which extends through the plug. A spring 36 is interposed between the piston 30 and the tubular plug 31 closing the left end of the casing I1. An orifice 38 is provided in the casing wall to i5 the right of the plug 33 and a suitably calibrated pressure responsive indicator 21 is connected by a pipe 28 with the casing to be acted upon by fluid between the friction tube and orifice.

The friction tube 35 is of such dimensions that its resistance to fluid flow varies with the viscosity of the fiuid while the orifice 38 ls of such dimensions that its resistance to fluid flow is substantially independent of the fluid viscosity. 'I'he pressure of the oil supplied to. the friction tube is maintained substantially constant as will sub- 10 sequently be described and therefore change of viscosity of the oil effects conjoint variation of the resistance to flow of the friction tube and the pressure differential across the friction tube with resulting change of pressure between the friction l5 tube and the orifice. As the resistance to ow of the orice is dependent upon rate of flow and is substantially independent of viscosity, and as the rate of fiow through the orifice is the same as through the friction tube, the pressure of oil between the friction tube and orifice is a measure of the rate of flow through the friction tube and is a function of the oil viscosity.

l'I'he pressure of the oil supplied to the friction Cil tube 35 is maintained constant by regulatory ac- 25.

tion of the valvel against and under the inf-luence of the spring 36. The pressure of the oil in the chamber between the plug 33 and the right hand end of the casing I1 is a function of its viscosity as previously pointed out and direct vis- 30 cosity readings are obtainable from the indicator 21.

The modification disclosed in Fig. 3 differs from the modification disclosed in Fig. 2 in that the plug 33 contains the orifice 38 and the friction 35 tube is carried by the right hand end. of the casing I1. In this modification, oil is supplied to the orifice at constant pressure and as its resistance to liow is dependent upon rate of flow and substantially independent of viscosity and 40 as the rate of iiow through the orice and friction tube is the same, the pressure of the oil between the orifice and friction tube is a measure of the rate of flow through the friction tube and .is a function of the oil viscosity. The indicator 21, therefore, gives direct viscosity readings.

In each of the modifications, oil is supplied to either a friction tube or an orifice at constant pressure and the oil pressure between the crie ce and friction tube or between the friction tube and orifice is a function of the oil viscosity. The indicator' 21 is responsive to variation in the fluid pressure between the friction tube and orifice or between the orifice and friction tube and is suitably calibrated to give direct viscosity readings. In the modification disclosed in Fig. 2, increase of pressure between the friction tube and orice is indicative of viscosity decrease and vice versa, while in the modification disclosed in Fig. 3, increase of pressure between the orifice and friction tube is indicative of viscosity increase and vice versa.

It is of course understood that various modications may be made in the structure above described, without in any way departing from the spirit of the invention as dened in the appended claims. y 1

I'claixn:

1. A viscosimeter comprising a casing having an inlet port and a discharge port, a member mounted in said casing between said inlet and. outlet ports and dividing the casing into a first chamber and a second chamber, said member being provided with a port intermediate said inlet and said outlet ports, apiston valve movable inV said first chamber in response to the pressure of uid delivered through said inlet port for controlling uid flow therethrough and a pressure responsive. viscosity indicator communicating with said second chamber, one of said intermediate and outlet ports being a friction tube and the other being an orifice.

2. In a viscosimeter, a cylindrical casing having a partition dividing it into two sections, a piston` slidably mounted in one section, said casing having a -port across which said piston is reciprocable to control iow into the casing, a spring tending to oppose movement of the piston away from said partition, said partition being provided with a port and said casing having an outlet port, and a pressure responsive viscosity indicator connected to said casing between said two last-named ports of which one is a. friction tube and the other is an orice.

3. In a viscosimeter, a cylindrical casing having a partition dividing it into two sections, a piston slidably mounted in one section, said casing having a port across which said piston is reciprocable to control flow into the casing, a spring tending to oppose movement of the piston away from said partition, said partition being provided with an orice and said` casing having a friction tube outlet, and a pressure responsive viscosity indicator connected to said casing between said orice and friction tube.

4. In a. .viscosimeten a cylindrical casing having a partition dividing it in to two sections, a piston slidably mounted in one section, said casing having a port across which said piston is reciprocable to control ow into the casing, a spring tending to oppose movement 'of the piston away from said partition, said partition being provided with a friction tube and said casing having an outlet orice, and a pressure responsive viscosity indicator connected to said casing between said friction tube and orifice.

HARRY T. BOOTH. 

